Alloy



8, 1936. J. A, ZUBLIN 2,051,358

ALLOY Filed Aug. 6, 1934 JOHN A. ZUBLIN INVENTOR- ATTORNEY Patented Aug.18, 1936 UNITED STATES PATENT OFFICE ALLOY John A. ZublinlBel Air,Calif. Application August 6, 1934, Serial No. 738,683

Y ferrous alloys containing copper, and particularly with thosecontaining copper in excess of the amount soluble in the ferrous base sothat some copper appears as free particles finely dispersed throughoutthe mass.

I have found that the presence of copper in iron and iron alloys impartsdesirable physical properties to the final alloy. But the production ofiron-copper alloys is rendered difficult by the relatively lowsolubility of either metal in the other and the unusual fact that thetwo metals when slightly above the melting point are immiscible and sodo not readily mix, but, to the contrary, separate. Consequently, it hasbeen a problem to form a product having a sufliciently high percentageof copper to impart the desired properties, since by methods formerlyavailable the cop-.- per not dissolved forms large segregationsresulting in a non-uniform product, whereas copper in finely dispersedform is desired.

Although copper may be added to iron alone, or to various othercombinations of iron and other elements, the particular alloy which Ishall ex-.- plain as typical of my invention is a hard, wearresistantalloy initially made as a welding rod and deposited on the surface to befaced. Alloys of exceptional hardness find various industrial uses,chiefly and typically as bearing surfaces in journals and the like whereno lubrication is used and resistance to wear and abrasion are primaryconsiderations. Metals of this type are usually applied by welding to asteel body which is relatively softer and tougher and so machineable.The alloy is applied as an external layer or facing, and, as it is toohard to machine, is brought' to finished dimension by grinding.

Hard facing metals are apt to be very brittle and of low tensilestrength so that considerable difficulty is encountered in theirtendency to crack and spall during application and finishing and tobreak down under heavy usage. Increasing the toughness of the metal toremedy these difiiculties usually decreases the hardness and resistanceto wear.

It thus becomes a general object of my invention to make a ferrous alloycontaining copper in excess of the amount soluble in the ferrous base,and with an undissolved excess of copper occurring in small particlesevenly distributed throughout the final product.

Another object is a method of forming an alloy of iron and copper inwhich the copper is evenly distributed and is prevented from separatingfrom the iron during melting of the constituents, to

form large aggregations and consequently a nonuniform product.

It is also an object of the invention to provide a self-hardening,wear-resistant alloy of unusual hardness, but containing sufiicientcopper to remove excessive brittleness and make the deposited metalrelatively tough and durable.

A further object is to provide an alloy in the form of a welding rodcontaining in excess those constituents partially lost during weldingand fin- 1o ishing operations. Thus the final deposit is certain tocontain suflicient quantities of the several constituents to produce thedesired physical characteristics.

These objects are attained by first forming an 15 intimate mixture ofcopper with the ferrous base, the mixing being such as to insure an evendistribution throughout the mixture of the particles of copper, and thecopper being added in quantities in excess of those soluble in theferrous base. 20 Then the mixture is rapidly melted and rapidlycongealed while the copper is still uniformly dis- I tributed throughoutthe metal and before segregation can occur, so that the solid bodycontains the copper in a state of substantially uniform 5 distribution.

My improved hard metal alloy contains iron hardened with carbon,chromium and molybdenum and toughened by the addition of copper finelydispersed throughout the final product. A small amount of manganese ispreferably added, as will be explained, but does not materially aifectthe characteristics of the final deposit.

How the above and other advantages of my invention are attained will bebetter understood from the following description and the annexeddrawing, in which:

Fig. 1 is an end view of a preferred apparatus for forming welding rod;and

Fig. 2 is a longitudinal vertical section on line 2-2 of Fig. 1.

Figures 1 and 2 illustrate a preferred form of apparatus for fusingconstituents to form welding rods. The construction and operation ofthis device is set forth in greater detail in my companion application,"Method and apparatus for fusing metals, Ser. No. 738,684, filed on evendate herewith, and consequently only a brief description will be givenhere since my companion application may be referred to for furtherdetails.

Any suitable supporting means is indicated at It, upon which rests metalbase plate [2 of a mould unit. Resting upon opposed pairs of blocks l3and I4 is the cylindrical electrode assembly generally indicated at l5.Electrode l5 comprises a central cylindrical member l6 and a pair ofdisks I'I positioned one at each end of the cylinder l6 and held inplace by bolt l8.

A pair of refractory bricks are placed with their inner longitudinaledges upon top of cylinder l6 and their opposed faces 20a spaced a shortdistance apart to form, in conjunction with cylinder 16, a V-shapedmould or charge-receiving space 22 on top of cylinder IS. The outeredges of the bricks are adjustably supported by posts 24 threaded intostandards 25 on base l2. Cylinder I6 is preferably of carbon, but may beof any other electrically conductive material.

Carbon pencil 28 is mounted on clamp 29 on handle 30 so that it may beheld by an operator, and provides an electrode that may be movedlengthwise of the charge receiving space 22. The end of electrode 28 ispointed as indicated, in order to concentrate within a relatively smallspace the arc formed between the two electrodes.

Electric power is supplied from any suitable source by negative lead 32attached to electrode 28 and positive lead 33 attached to binding post34 on base plate 22, current passing to electrode l5 through blocks l3and I4.

After a suitable quantity of charge 38 is placed within mould 22 on topof cylinder I 6, an arc is struck at one end of the mould betweenelectrodes I5 and 28. The intense heat of the are rapidly melts thematerial at 31 beneath pencil 28, and as rapidly as the material meltsin one spot the arc is moved away from the melted portion of the chargeto be over unmelted charge so that the entire charge is progressivelymelted from one end to the other. As the arc moves on to directly heatfresh, unmelted charge, the already molten charge is immediately allowedto cool and forms a solid rod as at 39; and this cooling is very rapidbecause the mass of bricks 20 and electrode I5 is so large as not tobecome appreciably heated during exposure to the arc and consequentlythe heat from the fused charge is rapidly dissipated. In this way, thematerials are almost instantaneously fused and are then very quicklychilled to relatively low temperatures.

I describe this mould and method of using as a typical and preferredmanner of making a welding rod of my new alloy, but it will beunderstood that other methods and devices may be used.

In order to form a welding rod made of my improved wear-resistant alloy,the charge introduced into the mould comprises ferromolybdenum,ferrochromium, cast iron, and copper. Ferromanganese is also preferablyadded, though this latter may be omitted. These constituents areintroduced in the proportions shown by the following table in which thefirst column indicates the range of parts by weight, and the second andthird columns illustrate typical preferred proportions:

Table I Range A B 10.25 9.25 12.5 12.5 14.75 16.0 125 1' 5 Flux 1.0 110The frro-alloys are standard commercial products, the ferromolybdenumused containing about 68% molybdenum and 30% iron, the ferrochromiumcontaining about 70 chromium and 24% iron, and the ferromanganese 80%manganese and 14% iron. The two latter alloys usually contain asubstantial per cent of carbon, which is desirable.. These figures are,of course, only representative, for various grades of the alloys may beused. The copper is commercially pure; and

although iron may be introduced in other forms, cast iron is preferred.It will, of course, be understood that the iron and ferro-alloys containvarying amounts of impurities such as silicon, phosphorus, sulphur, andmanganese, but the quantity of all these constituents is very small andnot constant. Since in general their effect may be neglected, they aremerely considered as impurities, although silicon is shown separately inthe analysis below. The amount of manganese so introduced is negligibleand it is preferred to introduce this element in the form of acontrolled amount of ferromanganese.

Before introduction into the mould of the various substances, I havefound it preferable to crush or otherwise comrninute the constituents towhat may be termed a granular form in order to help obtain an evendistribution of the several constituents so that the welding rod will beas uniform as possible in composition. After comminution, the severalconstituents are measured out in proportions by weight as indicated inTable I, and are then introduced into a device suitable for mixing, forwhich purpose a ball-mill is preferred because of the intimate anduniform mixing obtainable with this device, resulting in a uniformdistribution of all constituents throughout the mixture.

In order to form a welding rod, a suitable amount of the mixed powderedconstituents is introduced into mould space 22 which is of a proper sizeand shape to form a rod suitable for gas or electric welding methods.The charge is then melted by means of an electric are as described, thelocalized heat of the arc melting but a small portion of the charge atany instant. In this manner there is obtained an almost instantaneousfusion of the metals, a very short duration of the fluid state, and avery rapid congealing. During even the short period of fluidity, theseveral constituents, with the exception of the copper, readily form asubstantially homogeneous alloy. Liquid iron and copper when elevatedsomewhat above the melting point are immiscible, so there is a tendencyfor the copper to segregate in relatively large bodies at or near thesurface of the rod. Rapid cooling of the fused materials checks thistendency before segregation of the copper occurs, and the metal freezeswhile the copper is still uniformly distributed, so that the welding rodproduced contains particles of free copper distributed throughout invarying sizes.

It is not essential that every cross sectional area of the finished rodshow an absolutely uniform composition, and of course this will not bethe case if the section passes through a relatively large body ofcopper. It is suflicient that each short length of rod be of the sameaverage composition, and the distribution of the constituents issufliciently uniform if this be the case.

There is some loss of all constituents, except the iron, by vaporizationand oxidation. Also some copper appears at the surface so that when therod is buffed after removal from the mould the copper loss is a littlehigher in proportion I a,oe1,scs 3 than the other elements, as may beseen in Table II, below.

The proportions of the several constituents required to produce a rod ofa given composition 5 will vary with the percentage compositions of theseveral ierro-alloys and with the loss of the elements during themelting and finishing processes. Because of this loss, certain of theconstituents are present in the original mixture in excess of l thequantities desired in the welding rod. Percentage compositions, areindicated below in Table II, in which the first column indicates theapproximate range in percentage composition of the various elements inthe mixture when used in the proportions oi the first column 0; Table I,the sec- "ond column indicates the preferred range of composition oithe. welding rod, the third column gives the analysis of a typicalwelding rod made from a mixture having the proportions of column 20 B,Table I, and the last column, the composition of a typical deposit:

The rod so produced is a basic mixture to which other metals may beadded to change the characteristics of the basic alloy according to thecharacteristics of the added metal. Thus higher proportions of chromiumor carbon harden the alloy but increase brittleness, and a higherproportion of iron makes for a softer, more weldable alloy.

Table I shows the inclusion of one part of fiux,

45 which is not taken into consideration in the formation of Table II.The addition of this material helps remove impurities from the rod as itis melted, these impurities forming upon the rod surface a slag which isremoved by bufilng.

50 When it is desired to form a bearing surface upon a body, this rod isapplied to the body to form an external coating thereon in the samemanner as any other rodv is applied, which will be understood by thoseskilled in the art. Dur- 55 ing the time of application, the depositremains in a molten condition for a short time, during which thetendency of the copper to separate from the iron brings a largepercentage of the copper to the surface of the weld. It is desired 50that a considerable percentage of the copper remain distributedthroughout the finally deposited metal, and it is for this purpose thatthere is present in the original mixture and in the rod 9. large amountof copper in excess 01' that finally 55 remaining in the deposit,because contact with the remainder of the metal of this large percentageof copper insures final retention in the alloy of the desired amount.

The surface of a rough deposit is covered with m a more or lesscontinuous film of copper. If, in a typical application, the roughdeposit is a quarter of an inch thick, about 20 to 40% of the thicknessof this application will be ground away touring the bearingsurface'tofinished dimen- 5 sions, and the portion 0! the weld soremoved carries with it most of the copper content of the applied metal.

The remaining metal presents a hard polished surface in which may beseen irregular bodies of free copper. A very few of the largest copper 5aggregations may be as much as a quarter of an inch in diameter, but areof the order of only a few hundredths oi an inch thick. Examination ofthe macrostructure discloses a large number of much smaller copperbodies ranging in size to those barely visible. Microscopic examinationof such a polished specimen at increasing powers of magnification,discloses increasingly large numbers of copper particles of decreasingsize; and this characteristic distribution of very minute free copperparticles has been observed at several selected magnifications rangingup to 5000 diameters. Such an examination proves that the remainingbearing metal contains copper uni formly dispersed throughout but invery finely divided form. This characteristic dispersion is found alsoin the rod producing the deposit.

As the molten metal cools it appears there is a. temperature zone inwhich the iron and copper are miscible so that some copper goes intosolution, for the microscopic examination discloses around each of thesmall bodies of free copper an irregular but easily seen zone whichappears to have a high percentage of copper in solution.

It will be noted in general that, while the copper content of either therod or the final deposit is somewhat less than the content of theoriginal mixture and the final range of particle sizes is perhapsgreater than in the original mixture, many of the copper particles havebeen broken up during the melting and welding into much finer particleswhich are dispersed throughout the deposit so that there is finallyretained both in the rod and in the alloy a substantially uniformdistribution of copper.

The dispersion of small copper bodies through the bearing metal changesthe physical characteristics of the applied metal, even though thecopper itself is not all in solution. This is indicated by the fact thatthe alloy without copper is very hard but quite brittle. The addition ofthe copper toughens the resulting alloy and removes excessivebrittleness to produce a metal that makes a very hard and durable facingsubstance.

It will be realized that the composition of the 5 final deposit willdepend upon the deposit thickness and the method and duration of theapplication, since during this procedure the applied metal will combineto a greater or less extent with the base metal and some of theconstituents will be lost as a result of continued exposure to hightemperatures. The composition also varies progressively from the outsideto the base metal. By way of example, a deposit was made upon a block ofmild steel with a rod containing no manganese 0' and then the outerportion ground away as described to form a substantially uniformsurface. Analysis of an average sample of this typical deposit (seeTable II, last column) after grinding showed that the metal beneath thesurface contained only 5.6% of copper, indicating that the mixture androd contained copper in excess, roughly to the extent of 5 and 3.5times, respectively, the copper content of the ground deposit. The usualcopper content is between 5% and 10%. 7 The largest loss of copperresults from grinding to finish the bearing surface. Addition of ironfrom the mild steel base increased the iron content to 60.3% as comparedwith about 50% in the rod, and it is preferable that the welding methodsbe such as to result in substantially this percentage.

Since the total percentage of iron and copper is approximately the sameas in the mixture and in the rod, percentages of the other constituentsdo not change materially, although there may be some loss of them duringboth the formation of the rod and the application of the deposit. Thechanges in total mass caused by additions and losses of certainindividual constituents of course effects a change in the percentage orrelative amount present of the other constituents. The carbon increasesroughly in proportion of the iron and remains at about 6% of the ironcontent. The combined percentages of silicon, carbon, and impurities donot normally exceed 6%.

The use of manganese is preferable but not necessary, and is preferredbecause in small amounts it improves the welding qualities of the alloyboth in first deposits and in repair layers, and because it is adeoxidizing agent. Most of the manganese is lost during the two heatsand little if any remains in the final deposit. In larger amounts (e.g., 6 parts of ferromanganese) the final alloy is softer and tougher.

The hardness of the applied metal is quite uniform, except when testedupon one of the larger copper bodies, which are softer naturally thanthe surrounding material. Tests upon many specimens have shown ascleroscope hardness ranging from about 70-85, with the average about7580.' It has been generally observed that when a repair layer isapplied, that is a second layer over a previously applied layer, thatthe repair layer averages about 5 points higher or approximately 80-85scleroscope. This increase in hardness is attributed to the fact thatthere is less dilution of the bearing metal with iron from the base towhich the facing is applied, but the increase in hardness is notaccompanied by any material increase in brittleness. The deposit retainsits hardness over a wide range of temperatures and may be used atrelatively high temperatures with no decrease in hardness. Heattreatment after application usually somewhat increases hardness. Initiallayers after quenching from 1550 F. and then drawing at 700 to 800 F.show an average hardness of 85-90 scleroscope.

The alloy bonds extremely well with the parent metal to which it isapplied, so that no difiiculty arises from a weak bond, the bond attimes being stronger than the applied metal itself. Further, when asecond or repair layer is applied over an old layer of bearing metal,the two layers fuse together very evenly and show no signs of crackingor developing zones of weakness along their junction.

I Although I have described my invention in connection with a particularalloy, the broader claims are not to be limited thereby, for theinvention is applicable generally to iron alone with copper or withother alloying agents than those mentioned, for the scope of theinvention is intended to include any ferrous composition in which thereis present undissolved copper in free particles finely dispersedthroughout the mass. Of course, changes in other elements may be made bypersons skilled in the art without destroying the advantages of the freecopper present. The term alloy" used in the specification and claims isused in a broad sense to include any combination of metallic elements.whether they result in chemical compounds, solid solutions, mechanicalmixtures, or any combination of these three conditions. i 5

I claim as my invention:

1. A welding rod, for forming a deposit having wear-resistantproperties, having the following composition: molybdenum 11 to 14%,chromium 13 to 16%, copper 15 to 25%, and iron substantially all of thereminder.

2. A welding rod, for forming a deposit having wear-resistantproperties, having the following composition: molybdenum 11 to 14%,chromium 13 to 16%, copper 15 to 25%, manganese trace to 15 1%, and ironsubstantially all of the remainder.

3. A welding rod, for forming a deposit having wear-resistantproperties, having the following composition: molybdenum 11 to 14%,chromium 13 to 16%, copper 15 to 25%, carbon 2.5 to 4%, 20 silicon traceto 1%, and iron substantially all of the remainder.

4. A welding rod, for forming a deposit having wear-resistantproperties, having the following composition: molybdenum 11 to 14%,chromium 2 13m 16%, copper 15 to 25%, manganese trace to 1%, carbon 2.5to 4%, silicon trace to 1%, and iron substantially all of the remainder.

5. A welding rod for forming a wear-resistant deposit of approximatelythe following composition: iron 60%, molybdenum 13%, chromium 15%,copper 6%, manganese .5%, carbon 3%, silicon .5%, and 1% of impurities.

6. A welding rod for producing a wear-resistant deposit of approximatelythe following composition: iron 55 to 65 parts, chromium and molybdenumtogether 25 to 35 parts, copper 5 to 10 parts, and about 5 parts ofcarbon, silicon, and minor elements.

7. A welding rod for producing a wear-resistant deposit of approximatelythe following composition: iron 55 to 65 parts, chromium and molybdenumtogether 25 to 35 parts, copper 5 to 10 parts, and about 5 parts ofcarbon, silicon, and minor elements; the rod containing copper in excessof the content of the final deposit.

8. A welding rod for producing a wear-resistant deposit of approximatelythe following composition: iron 55 to 65 parts, chromium and molybdenumtogether 25 to 35 parts, copper 5 to 10 parts, and about 5 parts ofcarbon, silicon, and minor elements; the copper content of the rod beingat least 3 times that of the deposit remaining after grinding to afinished bearing surface.

9. A facing of hard, wear-resisting metal applied by welding to aferrous base which after application and finishing has approximately thefollowing composition: iron 60%, molybdenum 13%, chromium 15%, copper6%, carbon 3.5%, 60 silicon .5% and the balance impurities.

10. A ferrous alloy containing: molybdenum 10 to 14%, chromium 13 to18%, copper 5 to 25%, and iron substantially all of the remainder.

11. A ferrous alloy containing: molybdenum 10 to 14%, chromium 13 to18%, copper 5 to 25%, carbon 2.5 to 4%, silicon trace to 1%, and ironsubstantially all of the remainder.

JOHN A. ZUBLIN.

